This invention relates to valves for modulating fluid flow in refrigeration systems. While the invention is described with particular detail with respect to such systems, those skilled in the art will recognize the wider applicability of the valve disclosed hereinafter.
Various varieties of valves for modulating fluid flow in refrigerating systems are known in the art. In general, present mechanical valves used as evaporator regulators or expansion valves in a refrigeration system accomplish their control function by using a pressure actuated pilot valve for controlling valve position. Operation of the pilot valve, in turn depends upon the pressure or temperature sensed at one particular point in the system, depending upon the kind of sensor employed with the valve. While such valves work for their intended purpose, they are not without problems in applicational use. Thus, the fact that valve operation depends upon a single sensed system variable limits the valve capability. Likewise, valve operation can be dependent upon a variable which the valve is intended to control. Consequently, valve operation can be unstable during operating periods when valve operation should be most stable for best system efficiency. Such valves also are characterized by complicated and relatively expensive construction.
The invention disclosed hereinafter overcomes these prior art deficiencies by providing a versatile electrically operated valve which is able to accurately and efficiently regulate temperatures, flows and pressures of a controlled system in response to any of a variety of system parameters, those parameters being measured electrically. The movable valve member is balanced and independent of fluid pressures in the system. The movable valve member also always is in positive control, so that valve position is directly controlled by the system parameters being monitored. Because system parameters are measured and processed electrically, a number of points on the system can be utilized to generate the valve control signal.
One of the objects of this invention is to provide a valve giving precise control of a refrigeration system by regulating pressure and temperature in the system.
Another object of this invention is to provide a balanced port valve design which operates independently of fluid pressure in the system.
Another object of this invention is to provide a balanced port valve design in which the plunger of the valve is under direct control in all operating positions of the valve.
Another object of this invention is to provide a lower cost valve assembly.
Other objects of this invention will be apparent to those skilled in the art in light of the following description and accompanying drawings.